In a semiconductor non-volatile memory device, a device using a ferroelectric substance has been studied for many years as a ferroelectric random access memory (FeRAM). Among such FeRAMs, a memory device having a configuration of replacing a volatile capacitor of a dynamic random access memory (DRAM) with a non-volatile ferroelectric capacitor is put into practical use taking advantage of power-saving feature.
Further, study has also been made for many years on a memory device of metal ferroelectric silicon (MFS) type or a memory device of metal ferroelectric insulator silicon (MFIS) type in which ferroelectric substance is applied for a gate insulating film.
On the other hand, a ferroelectric tunnel junction (FTJ) device in which polarization of the ferroelectric substance is detected by reading tunnel current flowing in the ferroelectric substance has also been studied. However, there is a problem in that it is highly difficult to integrate materials used in the related arts, such as BaTiO3 and PbZr0.5Ti0.5O3, with a large scale integration (LSI) technology using a complementary metal oxide silicon (CMOS).